Interaction between T. castaneum and mycotoxin-producing fungi present in milled grains

Abstract: This work aims to study the interaction between two organisms when they grow
together in maize flour: Aspergillus flavus Link and Tribolium castaneum Herbst. Two strains of A. flavus were used, one atoxigenic and the other producing aflatoxins. Trials involved a control of only maize flour, maize flour with insects, maize flour with fungi and maize flour with these both organisms (A. flavus and T. castaneum). The development of all these organisms in maize flour was observed. The mycotoxigenic strain of A. flavus produced aflatoxin B1 and B2. However, this production was significantly higher when the fungi was interacting with insects, exceeding the limits allowed by EU in food. AFG1 and AFG2 were not found in any of the treatments. The fungi development seemed to exert a negative effect on the insects survival, as it caused their death, regardless of the putative chemical defenses that this insect has towards other compting organisms, the benzoquinones. It was observed that the adults of red flour beetle promote not only the dispersal and growth of the fungi, as well as seem to stimulate mycotoxin production.